Step 4 – Download and Install ISAPI Rewrite

The biggest challenge with getting IIS 6 to work with WordPress is that Windows does not have a native ISAPI rewrite filter in the web server. You have to download and install one. There are many choices, but Ionic’s ISAPI Rewrite Filter is free and it works, so why make it complicated, use this…

Step 6 – Activate Multisite in WordPress

WordPress Multisite gives you 3 choices of how to differentiate your multiple websites: subdomain, subdirectory, or domain mapping. For simplicity, I chose to go with the subdirectory option because it uses the ISAPI rewrite filter that we have already installed, and it requires no further installations.

So as I said, I went with subdirectory differentiation for ease of installation, and it seemed to be more compatible with IIS since it required fewer installations. In fact, we are done with all the required installations, and we will now only need to modify some code to finish up.

Add this line to your wp-config.php file and save the file:

define(‘WP_ALLOW_MULTISITE’, true);

On the left column in the dashboard, you will see a new link called “Network” under “Tools.” Disable all of your plugins, and then click the “Network” link. Select “Sub-directories” for the Network type, give the network a title, and enter the admin e-mail address.

NOTE: If you see this error it’s because you installed WordPress more than 30 days ago: “Because your install is not new, the sites in your WordPress network must use sub-domains. The main site in a sub-directory install will need to use a modified permalink structure, potentially breaking existing links.” The work around solution is simply to ignore this message and change the line in the wp-config.php file that says “define( ‘SUBDOMAIN_INSTALL’, true );” to “define( ‘SUBDOMAIN_INSTALL’, false );” but be sure you backup your database before you try to go this route. If you are very worried about it, and you have a lot of posts, then you should consider using subdomains or domain mapping instead of subdirectories.

After you select the network type, title, and email, WordPress will display the code that is required for the wp-config.php and for the ISAPI rewrite filter. Copy the code that WordPress provides into the wp-config.php file as the WordPress directions explain. WordPress assumes the third chunk of code will be put into a file called “.htaccess” which would be correct if we were using Linux. Since we are using IIS 6 with the ISAPI filter we installed in step 4, we save the code that WordPress supplies for “.htaccess” but we save it in a file called “iirf.ini” and place that on the root of your WordPress web server.